Due to their performance, the applications of bottles and other containers formed of a biaxial drawing, blow-molded thermoplastic resin, such as polyethylene terephthalate (PET) resin, etc., are spreading greatly in a wide variety of fields, such as drink bottles, etc. Normally, such molded containers are manufactured by heating and melting a plastic material by an injection molding machine to injection mold test-tube-shaped preforms, conveying these preforms to a blow molding machine, and then guiding the preforms into the mold of the blow molding machine and performing the biaxial drawing blow molding processes of vertical drawing by a draw pin and blowing of compressed air into the preforms.
Various improvements have been attempted in the respective processes in order to increase the production speed of the manufacture of such containers. For example, for the processes of receiving preforms, which have been molded by an injection molding machine having a plurality of preform molding cavities aligned vertically and laterally, aligning these preforms in single rows, and conveying them to the blow molding machine side, a preform conveying device (referred to hereinafter simply as “conveying device”), such as shown in FIG. 6, has been used since priorly to improve the production speed.
The conveying device of FIG. 6 mainly comprises a conveyor part 32, and a preform feeder 33, having a function of aligning the orientation of preforms P in a fixed direction by the rotation action of a disk, and this conveying device receives, by means of the conveyor part, a plurality of preforms P, which have been unloaded by an unloading device 31 from an injection molding machine having a plurality of preform molding cavities, and supplies the preforms to preform feeder 33 to align the orientations of preforms P into single rows by using the centrifugal force due to the rotation of the disk and convey them to the blow molding process side.
However, if the production speed is to be increased further, the preforms must be handled in a state of higher temperature, and with the prior-art method illustrated in FIG. 6, the preforms can get damaged due to collision or friction of preforms with themselves or with device parts.
Also, due to the high probability for preform surfaces coming in contact with parts that make up the device, soiling of preform surfaces occurs at a high frequency.
This invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a device that receives preforms that have been molded by an injection molding machine having a plurality of preform molding cavities aligned vertically and laterally, aligns these preforms in single rows, and supplies them to a blow molding machine or other subsequent process side, wherein a conveying device of high production efficiency is provided under the technical theme of aligning the plurality of preforms in single rows at high speed, while eliminating contact of individual preforms with other preforms and minimizing the chances of contact with device parts.